Effects of changes related to T_max on the ice sublimation and re-freeze with models Tmax50 (top) and Tmax100 (middle) with T_max 50 and 100 K, respectively. The bottom plots show the results from Model Plateau with t_plat = 10 kyr. Left: ice thickness (black lines) and grain temperature (red; the thicker lines show larger grains). Right: n/n(H₂) of major species in gas (dotted) and ice (solid lines). This is to be compared with Model Standard in Fig. 2, where T_max = 150 K and t_plat = 0. The scale changes for the secondary y-axis (T_d) in the left plots.